This invention relates to a plumbing tool.
More particularly, the invention concerns improvements in plumbing tools of the type used for temporarily plugging water pipes, gas pipes and the like which normally contain fluid or gas under pressure.
In a particular respect, the invention concerns improvements in plumbing tools of a type which utilize a radially expandable cylindrical gasket carried at the end of an elongate rod.
When soldering various sections of pipe together, it is essential that the pipes be completely dry before the soldering begins. If the pipe is wet, then it is nearly impossible to obtain a watertight solder joint. When working with existing plumbing systems, the standard practice is to shut off the water system prior to commencing the start of soldering. However, water within the system often does not drain out easily. The result is that water continues dripping from the pipe long after this water system has been shut off. The dripping of water prevents the plumber from working with a dry pipe in order to obtain a watertight solder joint.
The prior art includes numerous examples of plumbing tools of the general type which involve a radially expandable cylindrical rubber gasket carried on the distal end of an elongate rod which can be inserted through a gate valve into the interior of a water pipe, gas pipe or the like. After insertion within the pipe, axially force is applied to the cylindrical gasket, causing it to expand radially to temporarily plug the interior bore of the pipe. Such tools are disclosed, for example, in U.S. Pat. No. 4,529,007 to Goforth, U.S. Pat. No. 3,993,103 to Hammer, U.S. Pat. No. 2,462,748 to Johnson and in U.S. Pat. No. 1,850,040 to Turner.
As disclosed by the Hammer, Johnson and Turner patents, such tools typically exert axially pressure on the cylindrical gasket by rotation of a threaded elongate rod relative to an internal threaded bushing. Such relative rotation of the bushing, in-turn, exerts axially force toward the distal end of the rod on the intermediate cylindrical sleeve disposed around the rod. The distal end of the sleeve, in-turn, applies axially force in the distal direction which causes compression of the gasket member and, consequently, radially expands the gasket member to plug the bore of the pipe.
Unfortunately, none of these patents disclose a device which permit the temporary plugging of a water pipe and the subsequent desoldering and removal of an unwanted valve or fitting without removal of the plug valve from the pipe. Simply, the tools disclosed in the Hammer, Johnson and Turner patents disclose devices including handle means which are incapable of telescopically receiving the bore of a plumbing valve. For example, the elbow handle of Turner is formed with a radius too small to permit a valve to be received. In addition, Hammer and Johnson disclose handle configurations which are too large to be introduced into the bore of a plumbing valve. Accordingly, none of these devices are configured to permit a valve to be de-soldered from a pipe and thereafter to be removed and replaced while the plug valve is in operation obstructing the flow of water or gas in the pipe.
Alternatively, my prior U.S. Patent, U.S. Pat. No. 5,363,881, discloses a plumbing tool for temporarily plugging a pipe including a rotating handle which is configured to permit the handle to be received within the bore of a gate valve such that the gate valve can be selectively removed or installed to a pipe while the plug valve operates to plug the water or gas pipe. Unfortunately, the rotatable handle disclosed in U.S. Pat. No. 5,363,881 requires moving parts leading to unnecessarily complicated manufacture and expense.
Accordingly, it would be highly desirable to provide a plumbing tool of the general type described above which is adapted to temporarily plug a water pipe or gas pipe which can be maintained in place when a valve is being removed and replaced.